Researchers at the National Institutes of Health (NIH) in the United States have found, in a new data analysis, that taking a daily supplement containing antioxidant vitamins and minerals can slow the progression of dry age-related macular degeneration (AMD) in its later stages, which could help people with the condition maintain their central vision.
To reach this conclusion, the scientists reviewed the original retinal images of participants in the Age-Related Eye Disease Studies (AREDS and AREDS2) and found that, in individuals with advanced dry AMD, the antioxidant supplement slowed the expansion of areas of geographic atrophy towards the central foveal region of the retina. The study has been published in the journal Ophthalmology.
The only approved treatments to slow the progression of geographic atrophy (GA) in age-related macular degeneration (AMD) require frequent intraocular injections and have modest efficacy, significant risks, and high costs. Thus, the purpose of this study was to determine whether oral supplements slow the progression of GA in AMD.
“We have known for a long time that AREDS2 supplements help delay the progression of intermediate to late AMD. Our analysis shows that they may also delay disease progression in people with late dry AMD.”
“We have known for a long time that AREDS2 supplements help slow the progression of intermediate to late AMD,” said Tiarnan Keenan, MD, of NIH’s National Eye Institute (NEI) and senior author on the study. “Our analysis shows that taking AREDS2 supplements may also slow disease progression in people with late dry AMD.” “These findings support continued use of AREDS2 supplements by people with late dry AMD.”
Effectiveness of AREDS and AREDS2 supplements against AMD types
In their new analysis, the researchers examined the original retinal images of participants in the AREDS (318 participants, 392 eyes) and AREDS2 (891 participants, 1,210 eyes) trials who developed dry AMD. They assessed the location and rate of expansion of the areas of geographic atrophy. They found that for those with geographic atrophy in central vision, the supplements offered little benefit. However, for the majority who developed geographic atrophy away from the fovea, the supplements were able to slow expansion toward the fovea by about 55% over an average of three years.
In the early and middle stages of AMD, the light-sensitive retina at the back of the eye builds up yellow deposits of fatty proteins called drusen. As AMD progresses to the advanced stage, people may develop leaky blood vessels (“wet” AMD) or lose regions of light-sensitive cells in the retina (“dry” AMD). Geographic atrophy in these areas slowly expands over time, causing progressive loss of central vision.
The original AREDS trial found that a supplement containing antioxidants (vitamins C and E, and beta-carotene), along with zinc and copper, could slow the progression of mid- to late-stage AMD. The subsequent AREDS2 trial found that replacing the antioxidants lutein and zeaxanthin with beta-carotene improved the supplement’s effectiveness and eliminated certain risks. At the time, neither trial observed additional benefits once participants had developed late-stage disease.
That initial analysis did not consider a phenomenon in late-stage dry AMD known as “foveal sparing.” Although all areas of the retina are sensitive to light, the region responsible for the sharpest central vision is called the fovea. Many people with dry AMD first develop geographic atrophy outside this foveal region and only lose their central vision when areas of geographic atrophy expand into the fovea.
“Our high-acuity central vision is essential for tasks such as reading and driving. Since there are few therapeutic options for people with advanced dry AMD to preserve or regain their vision, antioxidant supplementation is a simple measure that can slow central vision loss, even in those with advanced disease,” Keenan said. “We plan to confirm these findings in a dedicated clinical trial in the near future.”
Source: NIH
